L2 Herpes Viruses II
Epstein & Bar Virus
What is Epstein Bar Virus?
A newly observed type of herpes virus found in cultured lymphoma cell, that affects B lymphocytes
lineage.
Name EBV natural host.
Humans
What happens in case of EBV infection?
- Latency and periodic activation
- Lifelong persistence
Infection occurring in childhood is asymptomatic
What is the source and method of EBV infection?
Saliva Ü oral contact, hence why it is called kissing disease
In which form is the virus not highly contagious?
- Droplets
Ü Oral, not Respiratory
- Aerosols
Where is the virus shed? Why?
Oropharyngeal secretions after primary infection and intermittently afterwards
Where does viral replication take place? What proteins are encoded?
In differentiated epithelial cells.
Proteins encoded are gP350 and gP220
What are gP350 and gP220 proteins?
Proteins that mediate the attachment to CD21 receptor.
What cells express CD21 receptors?
- Mature resting B-lymphocytes
- Stratified squamous epithelium of the oropharynx, salivary glands, and ectocervix
What happens to EBV in latent state?
It maintains its life within B-lymphocytes
Summarize the pathogenesis of EBV
, EBV Enters
Spreads to Pharyngeal Local Entry to B-lymphocytes
other cells Epithelial Cells Multiplication Bloodstream Infection
though CD21
receptors
What are the two types of changed induced in B-Cells?
a. Virus becoming latent inside B-Cells
Indefinite growth of B-Cells by polyclonal B-Cell proliferation Ü Cells are immortalized.
Newly transformed cells are then able to produced multiple types of immunoglobulins.
Non-specific antibodies: IgM, IgG, and IgA
Contain Heterophile Antibodies Ü Antibodies induced by external antigens
b. Lysis of infected B-Cells
Results in cell death and the release of mature progeny virions
The parental virus (virion) gives rise to numerous progenies, usually genetically and
structurally identical to the parent virus.
Atypical lymphocytes are seen in blood smears
Most immunodeficient patients have lymphomas containing EBV
What is X-Linked Lymphoproliferative Syndrome?
A rare primary immunodeficiency disorder. People with XLP have an increased risk of EBV infection.
List the clinical features of EBV:
A. Infectious Mononucleosis/Glandular Fever
Primary infection seen in the age group between 15-25.
Its incubation period if 30-50 Days (4-8 Weeks)
Abrupt onset of:
- Sore throat, cervical lymphadenopathy, fever, malaise, and headache.
- Swear and gastro-intestinal discomfort
- Pharyngitis accompanied by a grayish white membrane
- Intermittent fevers
- Drenching sweats
- Transient rash
- Splenic enlargement and tenderness
- Acute airway obstruction
Epstein & Bar Virus
What is Epstein Bar Virus?
A newly observed type of herpes virus found in cultured lymphoma cell, that affects B lymphocytes
lineage.
Name EBV natural host.
Humans
What happens in case of EBV infection?
- Latency and periodic activation
- Lifelong persistence
Infection occurring in childhood is asymptomatic
What is the source and method of EBV infection?
Saliva Ü oral contact, hence why it is called kissing disease
In which form is the virus not highly contagious?
- Droplets
Ü Oral, not Respiratory
- Aerosols
Where is the virus shed? Why?
Oropharyngeal secretions after primary infection and intermittently afterwards
Where does viral replication take place? What proteins are encoded?
In differentiated epithelial cells.
Proteins encoded are gP350 and gP220
What are gP350 and gP220 proteins?
Proteins that mediate the attachment to CD21 receptor.
What cells express CD21 receptors?
- Mature resting B-lymphocytes
- Stratified squamous epithelium of the oropharynx, salivary glands, and ectocervix
What happens to EBV in latent state?
It maintains its life within B-lymphocytes
Summarize the pathogenesis of EBV
, EBV Enters
Spreads to Pharyngeal Local Entry to B-lymphocytes
other cells Epithelial Cells Multiplication Bloodstream Infection
though CD21
receptors
What are the two types of changed induced in B-Cells?
a. Virus becoming latent inside B-Cells
Indefinite growth of B-Cells by polyclonal B-Cell proliferation Ü Cells are immortalized.
Newly transformed cells are then able to produced multiple types of immunoglobulins.
Non-specific antibodies: IgM, IgG, and IgA
Contain Heterophile Antibodies Ü Antibodies induced by external antigens
b. Lysis of infected B-Cells
Results in cell death and the release of mature progeny virions
The parental virus (virion) gives rise to numerous progenies, usually genetically and
structurally identical to the parent virus.
Atypical lymphocytes are seen in blood smears
Most immunodeficient patients have lymphomas containing EBV
What is X-Linked Lymphoproliferative Syndrome?
A rare primary immunodeficiency disorder. People with XLP have an increased risk of EBV infection.
List the clinical features of EBV:
A. Infectious Mononucleosis/Glandular Fever
Primary infection seen in the age group between 15-25.
Its incubation period if 30-50 Days (4-8 Weeks)
Abrupt onset of:
- Sore throat, cervical lymphadenopathy, fever, malaise, and headache.
- Swear and gastro-intestinal discomfort
- Pharyngitis accompanied by a grayish white membrane
- Intermittent fevers
- Drenching sweats
- Transient rash
- Splenic enlargement and tenderness
- Acute airway obstruction
